development of 10-mev l-band electron linac for...

1/21한국물리학회 가을 학술논문발표회, 2007년 10월 18~19일, 제주

Development of 10Development of 10--MeV LMeV L--bandbandElectron Electron LinacLinac for CESCfor CESC**

*Work supported by KAPRA, # [email protected]

양 해룡#, 김 상훈, 장 성덕1), 손 윤규1), 권 세진1),

박 성주1), 오 종석1), 조 무현, 남궁 원

포항공과대학교 물리학과, 1)포항가속기연구소

한국물리학회 가을 학술논문발표회2007년 10월 18~19일, 제주


IntroductionIntroduction

• L-band traveling-wave electron linac

• Irradiation applications

• 10 MeV and average 30 kW

• Single klystron (pulsed 25 MW)

• Single accelerating column

• Vertical mount


Accelerator ParametersAccelerator Parameters

- 2.3 MeV/°CTemperature Shift Factor

- 4.7 MeV/ABeam Loading Factor

4.2 MV/mAverage Accelerating Gradients

40°C ± 1°COperating Temperature

0.8 μsRF Filling Time

2π/3 modeOperating Mode

Disk-loadedShape of Cell

Constant-impedance

Type of Structure

Accelerating Structure Parameter

35 kWAverage Beam Power

90%Beam Transmission Rate

1.4 APulsed Beam Current

10.7 MeVBeam Energy

Beam Parameter

6 μsPulse Length

1.6 APulsed Beam Current

80 kVHigh Voltage

E-gun Parameter

60 kWAverage RF Power

350 HzRepetition Rate

7 μsPulse Length

25 MWPulsed RF Power

1.3 GHzOperating Frequency

RF System Parameter


System LayoutSystem Layout

KlystronModulatorCCPS & Control Panel

Accelerator

Waveguide

E-gun Pulser Temp.Controller

To be installed at CESC (Cheorwon Electron-beam Service Center)


PB: Pre-buncher IP: Ion PumpPGV: Pneumatic Gate Valve PS: Phase ShifterATT: Attenuator BEM: Beam Energy MonitorBCM: Beam Current Monitor

Accelerating Column

ATT

Solenoid Magnet PS

Load

Modulator

PS

E-Gun

PGV

BEM

PB BCM

IP

IPIP

PGV

IP Controller

E-gun Heater PS

E-gun HV Pulser RF Window RF Window

Klystron

Vacuum GaugeController

Cooling WaterDistributor

TemperatureController

Source RF Generator

Master Trigger

Vacuum GaugeController

Steering Coil Controller

IP ControllerBeam Diagnostics

System

Cooling Stand

Inverter

Schematic Diagram of Schematic Diagram of LinacLinac SystemSystem

Beam Scanner


Beamline ConfigurationBeamline ConfigurationE-gun PGV

Pre-buncherSteering coil

SolenoidsMagnets

Accelerating Column

BCM

RF WindowVacuum System

Waterload

PGV The beam scanner system is followed by this drift tube.

Iron-wrappedSolednoids

Magnet


Accelerating ColumnAccelerating Column

Bunching Section

Normal Section

0.06231.00Normal

0.04150.985th buncher

0.04310.924th buncher

0.04420.883rd buncher

0.04890.752nd buncher

0.05380.651st buncher

Attenuation Coefficient

(Nep/m)

Phase velocity / cCell

Cell Characteristics

-5

-4

-3

-2

-1

0

1

2

3

4

5

0 5 10 15 20 25 30

Cavity Cell Number

RF

Phas

e D

evia

tion

(deg

.)

Phase shift for cavity cellCumulative phase shift for per cell relative to No.0


RF CouplersRF Couplers

Shorting bar

Tapered W/G

W/G to Coax adapter Network analyzer

(Agilent E8362B)

1 2

)( 2/2 πωz

)( 3/22 πωz

)(2 mz ω)(1 ωz

)( 2/πωϕ

)( 3/2πωϕ

)( mωϕ

2/)( 3/22/ ππ ωωω +=m

Measurement Setup(Khyl’s mothod on TRwave coupler)

Impedance Smith-chart

-120.6°-119.9°

179.4°179.2°

117.7°120.1°

Output couplerInput coupler

)( 2/πωϕ)( mωϕ

)( 3/2πωϕ


Focusing SolenoidsFocusing Solenoids

32440005

32440004

32360003

32320002

3.620001

Current (A)

Ampere-turn

Solenoids

1 2 3 4 5

Solenoids Characteristics

Powered by single DC power supply

0 50 100 150 200 250 3000

250

500

750

1000

1250

1500

Long

itudi

nal M

agne

tic F

ield

(G)

Longitudinal Distance (cm)

Longitudial B-filed


Waveguide Network with Coax LineWaveguide Network with Coax Line

e-Beam

KlystronOutput W/G

RF power25 MW-pulsed60 kW-average

High-power W/G Load

W/GStraight Section

W/GE-bend

W/GE-bend

VariableΦ-Shifter

W/G-D/C70 dB

W/GE-bend

Low loss Dielectric Coaxial Cable ( ~4 m long)

Pre-buncher

e-Gun

L-bandAccelerating

Column[IHEP in China]

W/G-D/C70 dB

Arc Sensing

View Port

L-band Waveguide Network

VariableAttenuator

W/GVacuum

Pumping port

Components inside the red boxes are filled with SF6 gas.

W/GVacuum

Pumping port

RF Window[Thales]

RF Window[Thales]

W/GStraight Section

W/GGas Feeding Port

Arc Sensing

View Port

W/GGas Feeding Port

Coax. D/C~53 dB

W/G-D/C 70 dB

W/GStraight Section

Arc Sensing

View Port

Components inside the blue boxes are operated under vacuum. W/G

CX-DC38 dB

W/G-CoaxConverter

Low- powerW/G Load


Klystron Klystron

1.7 μPervPerveance

28 V / 25 AHeater

230 ABeam current

264 kVCathode voltage

7 usRF pulse duration

300 WPeak drive power

60 kWRF output average power

30 MWRF output peak power

1.3 GHzFrequency

SpecificationsThales TV2022D Tube

1 : 13 Pulse Transformer


Pulse ModulatorPulse Modulator

CX2412X

15 A maxAverage anode current

15 kA maxPeak forward current

50 kV maxPeak forward voltage

8 unitsNumber of Units

30 kWAverage Output Power

45 kVOutput Voltage

33 kJ/secPeak Charging Rate 1: 13

2.2 μHInductor

50 nFCapacitor

15 stagesNumber of Stages


HighHigh--voltage Pulse Testvoltage Pulse Test

Time (μs)0 2 4 6 8 10

247.72 kV

Load beam voltage

Load beam Current

246.4 A

12

10 HzRepetition Rate

9.3 μsPulse Width (70 %)

42 kVCharging Voltage

246.4 ALoad Current

247.72 kVLoad Voltage

1 kΩLoad Impedance

Test Result


S

Control SystemControl System

E-gun HV Pulser

IP Controller

Vacuum GuageController

BCM

W/G Power Detector - 1F, 2, 3

Remote PC

Modulator Control

Cooling waterControl

Conveyor beltControl

Radiation & Protection

Control

Main

Control

ControlInterlockMonitoring

F

F

F

S

S

S

S

S

S

S

F

RS485

S

Solenoid Magnet PS

Steering Coil PS

Arc Detector- 1, 2, 3

W/G Power Detector - 1R

PGV - 1,2

PGV ControllerF

F

E-gun Heater PS

MasterTrigger

F

AcceleratorControl


Beam Commissioning ScenarioBeam Commissioning Scenario

89%Obtain the optimum condition

by the commissioningof the pre-buncher.

on1.625 MWononOperationCondition7.

77%Raise the input power until

the output beam energyat the operation condition.

off1.6to 25 MWononNominal

RF Power6.

86%Raise the input currentat the operation condition.offto 1.612 MWonon

NominalCurrent5.

85%Raise the input power

Until the outputbeam energy is 10 MeV.

off0.1to 12 MWononRF On4.

100%Turn on the solenoids.

Adjust the steering coil refer tothe simulation result.

off0.1offonre-adjustSolenoids

On3.

87%Search the max. transmissioncondition of the steering coils.

Find the offset rate.off0.1offoffonAlignment

Check2.

Check the outputbeam current.off0.1offoffoff

InitialCondition1.

Goal(transmission)RemarksPre-

buncher

InputCurrent

(A)

Input RF Power

(into acc.)SolenoidsSteering

CoilsStep


Beam Commissioning Beam Commissioning –– Alignment CheckAlignment Check

1˚misalignment no output beam

Initial condition: no power, no solenoid, no pre-bunching,operation the E-gun emitting 0.1 A only

Steering coils find the value of the misalignment

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.2 0.4 0.6 0.8 1Misalignment angle (deg.)

Tran

smis

sion

rate

Input beam current: 0.1 A

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.2 0.4 0.6 0.8 1

R-direction E-gun position offset (cm)

Tran

smis

sion

rate



- 2

- 1 .5

- 1

- 0 .5

0

0 .5

1

1 .5

2

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0L o n g i t u d in a l p o s i t io n ( c m )

x, y

pos

ition

(cm

)

x m e a nx 9 9 %x 1 %y m e a ny 9 9 %y 1 %

- 2

- 1 .5

- 1

- 0 .5

0

0 .5

1

1 .5

2

0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0L o n g i t u d in a l p o s i t io n ( c m )

x, y

pos

ition

(cm

)

x m e a nx 9 9 %x 1 %y m e a ny 9 9 %y 1 %

Beam Commissioning Beam Commissioning –– Solenoids OnSolenoids On

Focusing by solenoids 100% transmission

1° misalignment, solenoils on

Re-adjusted by steering coils

Re-adjusted by steering coils refer to simulation result

Beam Size

Beam Size

Optimum condition


0.7

0.75

0.8

0.85

0.9

0.95

1

0 5 10 15 20 25

Input Power (MW)

Tran

smis

sion

0

2

4

6

8

10

12

14

16

18

Ener

gy (M

eV)

TransmissionEnergy (MeV)


Beam Commissioning Beam Commissioning –– RF OnRF On

Raise the RF power at 12 MW: Beam energy limited by 10 MeV due to neutron production


0.7

0.75

0.8

0.85

0.9

12 15 18 21 24 27 30Input Power (MW)

Tran

smis

sion

rate

0

4

8

12

16

Ener

gy (M

eV)


Input current: 1.6 A

Beam Commissioning Beam Commissioning –– Nominal ConditionNominal Condition

Raise the input current to nominal value: 1.6 A

Raise the RF power to nominal value: 25 MW

0.8

0.82

0.84

0.86

0.88

0.9

0 0.4 0.8 1.2 1.6 2Input Current (A)

Tran

smis

sion

rate

0

2

4

6

8

10

Ener

gy (M

eV)


Input RF power: 12 MW

nominal value

nominal value


Beam Commissioning Beam Commissioning –– Operation ConditionOperation Condition

Scanning the transmission rate during change the pre-buncher phase

Pre-buncher optimizing ΔφPB 10˚, transmission 90%, 10.7 MeV

0

2

4

6

8

10

12

14

16

0 60 120 180 240 300 360Phase difference (˚)

Ener

gy (M

eV),

Pow

er (M

W)

0

0.2

0.4

0.6

0.8

1

Tran

smis

sion

rate

Energy (25MW, 1.6A)Power (25MW, 1.6A)Transmission rate

Input current: 1.6 APre-buncher input power: 3.75kW

max. power point


Current Status and PlanCurrent Status and Plan

Klystron & Modulator• Fabrication and Assembling finished.• PFN to be tuned for the flat-top requirement.• Installed at the CESC site.

Waveguide and Coaxial-line • Ready to installation.

Accelerating Column• Delivered to Pohang.• Beamline also to be assembled.

Under Development• Beam Scanner• Cooling System• Control System

Commissiong is planned this year.

development of 10-mev l-band electron linac for...

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